Hydroxyalkyl Alkyl Cellulose Particle Design for Tablet Strength
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Solution Overview
Problem
Existing sustained-release preparations face challenges with hydroxypropyl methyl cellulose (HPMC) due to its low compressibility, leading to tablet strength issues and tableting failures, while other additives like crystalline cellulose and low-substituted hydroxypropyl cellulose are water-insoluble and unsuitable for forming gel matrices.
Innovation Solution
A hydroxyalkyl alkyl cellulose with a volume-based average particle diameter of 50 to 100 μm, a volume fraction of fibrous particles between 45 to 70%, and a low volume fraction of fine particles (<2.0%) is developed, enhancing flowability and compressibility, allowing for the production of tablets with high hardness and reduced tableting pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HPMC is used as the binder in matrix type sustained-release preparation, then the gel matrix can be formed and sustained-release characteristics can be achieved, but the tablet strength is insufficient and tableting failures occur due to low compressibility
Solution Approach 1:
The patent combines HPMC (for gel matrix formation and sustained-release properties) with hydroxyalkyl alkyl cellulose (for compressibility and tablet strength) to create a composite binder system. This allows both sustained-release characteristics and adequate tablet strength to be achieved simultaneously, resolving the contradiction between HPMC's gel-forming capability and its poor compressibility.
Solution Approach 2:
The patent modifies the particle size parameters of the hydroxyalkyl alkyl cellulose to 50-100 μm, which optimizes its compressibility and flowability. This parameter change enables the additive to improve tablet strength while maintaining good flow characteristics during tableting, thus resolving the contradiction between tablet strength and tableting reliability.
2Strength
If crystalline cellulose or low-substituted hydroxypropyl cellulose is used as additive to improve compressibility, then high compressibility is achieved, but water-insolubility prevents gel matrix formation
Solution Approach 1:
The patent uses hydroxyalkyl alkyl cellulose with specific substitution parameters (degree of substitution and hydroxyalkyl group composition) that balance water-solubility for gel matrix formation with compressibility for tablet strength. This parameter optimization allows the additive to serve dual functions without the limitations of completely water-insoluble alternatives.
3Strength
If hydroxyalkyl alkyl cellulose with larger particle diameter (≥50 μm) is used, then compressibility is improved, but mixing properties and flowability during production are insufficient
Solution Approach 1:
The patent optimizes the particle size parameter of hydroxyalkyl alkyl cellulose to a specific range of 50-100 μm. This parameter change achieves the optimal balance between compressibility (improved by larger particles) and flowability/mixing properties (improved by controlled particle size distribution), resolving the contradiction between compressibility and ease of manufacture.
Data Source
AI summary
There is provided is a hydroxyalkyl alkyl cellulose exhibiting good flowability and high compressibility. More specifically, provided are a hydroxyalkyl alkyl cellulose having a volume-based average particle diameter, determined by dry laser diffractometry, of 50 to 100 μm, and having, on a basis of a dynamic image analysis to divide all particles into fine particles, spherical particles and fibrous particles, a volume fraction of the fibrous particles consisting of long and short fibrous particles relative to all of the particles of 45 to 70%, and a volume fraction of the fine particles relative to all of the particles of less than 2.0%; a solid preparation including the hydroxyalkyl alkyl cellulose; and others.